Wire-based communications apparatus, such as a data logger, often have more than one communication port. For example, a data logger available from the assignee of the present application, identified as Data Management System DMS II D/S, includes first and second communication ports. The first communication port includes a socket connector for plug-in connection to a hand-held computer for down-loading information from the data logger to the computer. The second communication port is adapted for connection to apparatus which provides wireless communication between an over-the-road vehicle and a home base via satellite. The second communication port is enabled, until a plug connector is engaged with the socket connector of the first communication port, with the plug connector changing the logic level of a control terminal of the socket connector which causes a multiplexer to route data to the first communication port instead of to the second communication port, as long as the plug connector is engaged with the socket connector. When the plug connector is disconnected from the socket connector, the multiplexer again routes communications through the second communication port.
The above mentioned data logger is often physically mounted on a refrigeration unit, with the data logger periodically recording information concerning the operation of the associated refrigeration unit. Such refrigeration units are often associated with refrigerated containers which are usually stacked upon each other to a predetermined height, which may reach as high as 23 feet (7 meters). It is thus very difficult for an operator who wishes to down load data to a hand held computer to make the necessary plug-in connection, requiring ladders or other means of elevation.
It would thus be desirable, and it is an object of the present invention, to be able to easily convert a socket connector dedicated to wire-based communication, to wireless communication, even when the socket connector has a control terminal which enables the communication port only when a plug connector is engaged therewith. It is further desirable, and it is another object of the invention, to be able to make the conversion of the socket connector to wireless communication, without continuously enabling the socket connector. In other words, it would be desirable to enable the socket connector only during actual wireless communication, returning communication to some other communication port when the wireless communication via the socket connector is not active.